Sound reproducing system and apparatus



M chgzs, 1935'. L S MON 1,996,034

SOUND REPRODUCING SYSTEM AND APPARATUS Filed Oct. 4; 1933 s Sheets-Sheet 1 INVENTOR Louis J51 0215.

ATTORNEY March 26, 1935. J smoNs 1,996,034

SOUND REPRODUCING SYSTEM-AND APPARATUS F iled. Oct. 4, 1955 s Sheets-Sheet 2 iNVENTOR Louis J' Simon;

ATTORNEY K March 26, 1935.

L; J. SIMONS I 1,996,034

SOUND REPRODUCING SYSTEM AND APPARATUS Filed Oct. ,4, 1955 3 Sheets-Sheet s INVENTOR Louis I Simona.

ATTORNEY 4 Patented Mar. 26, 1935 V UNITED STATES PATENT OFFICE SOUND REPRODUCING SYSTEM AND APPARATUS 6 Claims.

This invention relates generally to sound production processes and apparatus and is more particularly directed to a system for reproducing sound from vibrations photographically recorded 5 upon a strip of flexible material, as film, such as is utilized in the projection of motion pictures.

.As is well known, sound vibrations in the various ranges of high and low frequencies are photographically recorded in the production of a so- 10, called talking or sound picture adjacent one edge of the film which is defined as the sound track, the vibrations appearing as lines of varying thicknesses and being disposed horizontally, vertically or obliquely within the limits of the sound track,

depending upon the particular, photographing process that is followed. In the production of the commercial or standard 35 millimeter sound film the area available for the sound track has made it possible to obtain a degree of clarity in reproduction that produces eminently satisfactory results. However, there is a large demand for sound effects in conjunction with actions photographed on a 16 millimeter film, this demand being generally met at present by employing what are known as disc recordings, the discs on which the sound vibrations are impressed being connected to the picture projecting apparatus to function in synchronism with the film action. The disc apparatus possesses many features which materially limit its range of use and in an effort to overcome the disadvantages of the disc method of reproduction numerous attempts have been made to provide a satisfactory system or apparatus for reproducing sound photographically recorded on 16 millimeter film. While the sound vibrations may be successfully recorded upon'the sound track of lesser area that is afforded by the 16 millimeter film, the problem of reproduction is a much more difficult one than 40 was presented in the case of the latter, and in those instances where apparatus has been assembled for reproducing the sound vibrations from the 16 millimeter film, the results have been generally unsatisfactory, due to the poor quality of the reproduction, either in the high or low frequencies or in both, or because of the complicated nature of the apparatus and the neccssity for frequent and skilled adjustments during use that can only be performed by those experienced in the art, coupled with the high cost of production with a concomitant almost prohibitive market price. Since the 16 millimeter film is marketed primarily for home, educational, industrial and other uses where it is handled and exhibited by those who are not technically trained, as in the case of the standard 35 millimeter film, it will be manifest that any sound reproducing system, in order to satisfactorily meet the demand for sound-on-film reproduction must not only be of an extremely simple and economical construction, but must be capable of reproducing the recorded sound vibrations with a degree of clarity and definition that is at least comparable to the results attained in the 35 millimeter film sound reproducing apparatus.

There is not now available a sound reproducing system or apparatus which embraces those features of efficiency, simplicity, and economy of construction and operation that, as hereinbefore pointed out, are essential to successfully meeting the existing demand for reproduction of sound photographed on 16 millimeter film, and the general object of the present invention is to provide a sound reproducing system that will embody all of those attributes that will overcome the shortcomings of the prior types of apparatus that have been devised in the unsuccessful efforts to meet this demand and generally effeet a solution of the problem of reproducing sound from 16 millimeter film.

More specifically the object of my invention is to provide a simple and effective system for reproducing sound photographically recorded upon 16 millimeter film that may be readily associated with the various existing types of picture projection machines or apparatus, designed to operate with 16 millimeter film, without effecting changes or alterations therein, as well as being susceptible of incorporation in specially constructed apparatus, wherein operating elements may be common to both the picture projection mechanism and the sound system, thereby imparting to my invention a wide range of application and utility.

A further object of my invention is to provide a sound reproducing system of the type and possessing the characteristics aforesaid, wherein the necessity for micrometer optical and other adjustments, as in existing apparatus, is entirely eliminated, so that the maximum of efliciency in the functioning of the system may be attained at all times, even in the hands of the non-technical or unskilled operator.

Another important object of my invention is to provide a simplified optical system and mechanism for controlling the cooperation of the film therewith, whereby the image of the recorded vibration may be transmitted to the sound-head by utilizing any conventional light source of low voltage, in lieu of the costly specially designed high voltage lamps, my optical system possessing certain fixed characteristics of performance and eliminating the necessity for the frequent focusing and other adjustments that are essential to the functioning of optical systems of existing apparatus. Y

My invention also contemplates, in addition to the foregoing, numerous structural and other refinements, such as lamp-supporting devices whereby the source of light is adequately protected against detrimental vibrations which might be transmitted to the apparatus or system in transportation or use, together with mechanism which will prolong the effective life of the film by minimizing the wear at the sprocket openings and in other respects which will be more specifically emphasized in the detailed description of my invention.

Other objects and advantages flowing from the practicing of my invention will'doubtless become manifest as the description proceeds, and I would have it understood that'l reserve unto myself all rights to the full range of equivalents, both in structure and in use, to which I may be entitled under my invention in its broadest aspect.

For the purposes of this disclosure, I have elected to illustrate and describe a preferred embodiment of my system as associated with a standard type of projection machine designed to operate with a 16 millimeter film. However, this is merely illustrative, as my invention may take other forms and be employed in conjunction with apparatus for projecting the action photographed upon a standard 35 millimeter film, without departing from the spirit and scope hereof, as defined by the appended claims.

In the drawings: a

Figure l is a side elevation of a conventional motion picture projection apparatus having the elements of the sound head of my system associated therewith. I

Figure 2 is an enlarged top plan view of the soundhead assembly shown in Figure 1.

Figure 3 is a side elevation of a part of the structure illustrated in Figure 1, portions of certain elements being broken away to disclose the so-called sound sprocket of the head assembly.

Figure 4 is a part elevation of the sound head and cooperating parts of the projection apparatus.

Figure 5 is a longitudinal vertical section of the sound-head mounting.

Figure 6 is a transverse section of the photoelectric cell housing and cooperating light valve. Figure 7 is a View, in perspective, of the light beam prism bracket or mounting.

Figure 8 is a view in elevation of the exciting lamp and its telescopically mounted support.

Figure 9 is a perspective View of the lamp base holder or socket illustrated in full and dotted lines in the preceding figure, and

. Figures 10 and 11 are sectional elevations of alternative constructions of a preferred type of exciting lamp.

Referring now to the drawings in detail in which like characters of reference are employed to designate similar parts in the several views, 7 indicates the housing of a standard type of projection machine with which the customary film discharging and receiving reels or spools 8 and 9 are associated, the film in its passage from one reel to the other being led through the usual gate 10 between the light source and the lens barrel 11.

The sound-head assembly includes the preferably oblong supporting frame 12, which may be of cast or thick metal or formed of any other suitable material, one of the longer parallel sides thereof being provided with a pair of elongated apertures 13 and 14 to receive the screws 13 and 14 whereby said frame may be 'detachably and adjustably secured to the projector housing, in any feasible manner, as by the provision of a bolster or spacer 15 fixed to the housing by screws 16, in which the screws 13 and 14 are seated, or by direct connection thereto, in either of these preferred forms of application, existing threaded bores in the housing being utilized for the reception of the supporting screws, so that recourse to drilling and tapping operations in the mounting of my sound-head is unnecessary.

As will be observed, the frame-supported elements of my sound head assembly include a photo-electric cell, an exciting lamp therefor and an optical system interposed between the light source and the objective cell, each of these elements being independently housed, in a preferably cylindrical metallic casing, the respective housings being disposed in a horizontal plane below that of the lens barrel 11, with their longitudinal axes parallel to the corresponding axis of said barrel, the optical system housing 17 and the casing 18 for the exciting lamp 19 being concentric or in axial alinement. While this arrangement of the essential elements of the sound head may be deviated from, to meet different conditions in the application of my invention, I have found it extremely advantageous in producing a sound-head that may be readily associated with any of the existing types of standard pi ture projecting machines, without effecting alterations therein, the supporting frame being adapted to extend transversely of the front of the projector housing for fixture thereto, as hereinbefore described. Obviously, the front of the projection machine, because of the fact that it is clear of all mechanisms and control devices, except the protruding lens barrel, readily lends itself to the attainment of one of the'principal objects of my invention, as previously set forth, which resides in the provision of asound-head or sound-reproducing system which is susceptible of use in conjunction with picture projecting machines conforming to standard designs, so that the so-called silent projectors may be readily converted for reproducing sound photographed upon the film upon which the picture action is carried.

Due to the location of the sound-head frame across the front of the projector housing, and to avoid possible interference of certain elements thereof with the rays of the light beam projected from the lens barrel. 11, I find it preferable to utilize a right angle reflector prism, alined with the lens barrel 11 to project the beam transmitted therefrom at an angle of 90 degrees to the longitudinal axis of said barrel, this prism, indicated at 20, being mounted in a conforming support 21 having a friction hinge connection 22 with the bracket 23 fixed to the frame 15 to provide for arcuate movement on the axis of said hinge in framing the picture upon the screen. the range of adjustment being controlled by the curved slot 24 in the extension 25 of said support 21 which traverses a screw 26 located in the bracket 27 on the frame 15, a suitable locking nut 27 cooperating with said screw 26 to retain the support 21 in adjusted position. As will be seen from Figure 1 of the drawings, the support 21 for the reflector prism is above the horizontal plane of the top of the sound-head supporting frame 15 and is spaced forwardly of the lens barrel l1 sufficiently to permit of the manipulation of the head 11 of the lens barrel in the usual manner for focusing the light beam. In lieu of the prism 20, a reflecting mirror and a suitable prism mounted at the proper relative angles may be utilized for projecting the image upon the screen, it being manifest that the supporting means therefor may take other forms and be subject to other methods of adjustment for framing than herein shown.

From Figure 1 it will be noted that the film 28 passes from the reel 8 around the usual sprocket 29 to pass across the light aperture of the film gate 10 for engagement with a second sprocket 30 which hereinafter will be termed the sound sprocket. This sound sprocket is substituted for the lower feeding sprocket of the projecting apparatus and embodies a single line of teeth or projections 31, instead of the customary double row of peripheral protuberances, the width of the body of the sprocket being less than the width of the film 28 so that the portion adjacent that edge of the film which bears the sound track extends or projects beyond the peripheral wall of the sprocket, as clearly shown in Figure 2, for the purposes which will hereinafter be explained.

A suitably shaped support, as the bracket 32, fixed to the projector housing 37 by screws or the like 33 at a point below the sound sprocket 30, is provided for a prismatic mirror 34 that is adapted to transmit light rays of variable intensity to the photo-electric cell 35 through the alined longitudinally disposed elongatedslit 36 in the cell housing 37. The aforesaid mirror 34, as will be seen from Figure 2 of the drawings, is positioned at an angle of 45 degrees to the adjacent end of the adjustable head 38 of the optical system housing 3'7 and centered on the longitudinal axis thereof, the face of the sound sprocket 30 being recessed, as by the provision of the concave surface 39, for the purposes which will hereinafter become apparent.

The light rays that are effective upon the cell 35 emanate from the exciting lamp 19 which may be of the common automobile instrument board type operating upon a six volt current or may be one of correspondingly low voltage of standard or special design receiving its energy from the source from which the current for operating the projecting machine and the sound-amplifying medium used in conjunction with my soundhead is drawn. This exciting lamp is supported from a base 40 telescopically mounted within the housing 18 for relative longitudinal adjustment, the lamp being seated in a retaining socket, incorporated in said base, which may be of any preferred construction. However, in order to obtain the best results in operation, I utilize a specially designed socket as shown in Figure 9 which is of an annular configuration and formed with the usual bayonet pin slots 41 adapted to interlockingly engage the cooperating protuberances upon the lamp base, the said socket being provided with inwardly directed, preferably integrally formed radially spaced fingers 42 that are adapted to yieldingly engage with the wall of the lamp base when located within said socket. As will be obvious, due to the resiliency of these fingers, any detrimental vibrations transmitted to the socket, either during the functioning of the apparatus or in the handling or transportation thereof, will be dissipated therethrough, while at the same time they cooperate to hold the lamp firmly in place within the socket and maintain the requisite co-axial alinement of the lamp and the cooperating elements of the optical system. Any suitable means of connecting the lead 43 from the base 40 to the source of energy may be used, the said base in the present showing, being locked in the position to which it may be adjusted within its housing 18 by a screw 44.

The optical system includes lenses 45 and 46 suitably supported in longitudinally spaced relation within the aforesaid housing 17 which may be suspended from the frame 15 or otherwise connected thereto, or may be supported in seats conforming to the peripheral contour thereof provided in the opposite sides of the said frame, as in the present embodiment of my invention, the housing extending beyond the frame on either side. At one end, such extension of the housing 7 provides a positive support for the exciting lamp housing 18, said latter housing being formed with a shoulder or portion of constricted diameter, as at 18 to engage with the protruding end of the optical system housing for rigid connection thereto by the screw 47.

From the description of my invention thus far given it will be evident that the light rays emanating from the exciting lamp 19 will pass through the lenses 45 and 46 for intensified and concentrated projection from the focusing head 38 of said housing 17, in a beam which has a focal point substantially midway between said head and the free and unsupported head 28 of the film 28 upon which the photographs of the sound vibrations are superimposed, the light rays as the film traverses the sound sprocket 30 passing through the images of the vibrations upon the sound track in varying intensities, in the usual manner, and impinging upon the mirror 34 for transmittal, by reflection, to the photo-electric cell 35 which is connected to a suitable amplifying unit (not shown) by the leads 35 Due to the employment of an extremely narrow light valve, as the elongated slit 36, the amount of light admitted to the cell 35 is controlled to a degree that affords a maximum of selectivity in light admission so that it is entirely feasible in my apparatus to feed the film relatively slack past the effective light area of the optical system head, without producing an overlapping of the light frequencies within such area and the blurring or fuzziness in reproduction that would result were the same condition in the film feed to prevail in present forms of apparatus for reproducing sound-onfilm of the 16 m. m. type. In this connection, it may be pointed out that with light valves of existing apparatus, in order to approach a fair standard of reproduction, the film in its passage through the light zone must be maintained under a constant and relatively strong tension which, obviously, places undue strain upon the sprocket holes thereof and materially shortens the life of the film. Further, the film, in present structures, is led through a gate which provides a passage of substantially the same thickness as the film, so that in the event of film breakage and the necessity for splicing, if the film is to be continued in use, difficulties in feeding the overlapped ends of the spliced sections through thegate are generally encountered, the entire apparatus frequently becoming inoperative because of the jamming and tearing of the splice within the gate.

In my construction, not only is the strain upon the film materially lessened, but by usingonly a single row of teeth upon the sound sprocket 30,

for engaging one line of sprocket holes therein, the sound track is less susceptible to scratching or abrasion of the emulsion coating, which oftimes results, as the tensioned film of existing apparaagainst buckling, as the film traverses the periphcry of said sprocket and the idler 48 in its passage to the receiving reel 9.

The housing 37 of the photo-electric cell is fixed to the base member 3'7 by the circumferentially-spaced screws 49, the said base being rigidly fastened to a plate or bracket 50, as by a bolt and cooperating securing nut 51, the said plate or bracket forming a virtual extension of one side of the frame to which it is hinged as at 52 for rotative movement in a horizontal plane, as-shown by the dot and dash line of Figure 2. I have found this type of mounting for the photoelectric cell housing extremely advantageous, since the cell may be readily moved out of its functioning position to facilitate access to the sound sprocket in threading a film through the apparatus to the receiving reel, the said housing being firmly held in its normal position for the functioning of the cell, as heretofore described, by the embracing spring fingers 53 and 54 and the cooperating head-engaging finger 55, the semispherical protuberance 56 of which enters a com plemental seat centrally located in said housing head. The structure of the cell housing includes a suitable shutter or closure for the light admitting opening or valve36 which in the present showing, comprises a cylindrical member 57 complemental to the periphery of the housing upon which it is rotatable between the housing engaging elements 53, 54 and 55 to obstruct the light opening 26 or to permit of the passage of light therethrough to the housing enclosed cell. As clearly shown in Figure 6, this shutter is provided with a slit 58 of the same area as the slit 36 with which it is adapted to register upon the requisite radial adjustment of said shutter or closure relative to the housing 3'7, a lip 59 formed integrally with said housing providing a surface whereby manipulation of the shutter to the light valve opening or closing positions may be readily effected. .Obviously, with a closure of the type just described, a maximum of protection is afforded to the sensitive photo-electric cell against impairment or possible paralysis due to light seepage through thelight valve when the cell is not normally functioning, the shutter opening 58 traveling through an arc of at least 90- degrees from the light valve 36, when the shutter is moved to closed position.

In Figures 10 and 11 I have shown types of exciting lampsthat may be advantageously employed in utilizing my invention, the lamp illustrated in Figure 10 including the usual base 60 and glass vessel or container 61 cemented thereto, which embodies a mount 62 from which a heatresisting element tubular in shape with a portion of its wall cut away from end to end as at 63, is supported by the pillars 64, which are preferably four in number to adequately brace said element and the filament 65 retained therein, the light resulting from a condition of incandescence in said filament being emitted through the longitudinal slit 63. The construction of the lamp of Figure 11 is generally similar, except for the fact that the heat-resisting element is in the form of a solid cylinder 66 in which the filament 65 is virtually embedded, a portion of said cylinder being cut away from end to end to form a sub stantially V-shaped light-emitting trough 67, the

apex thereof being occupied by the coaxially alined A lamp of either of the portion of the filament. types just described is most economical to construct and because of the advantageswhich fiow from the mode of supporting the filament will have extremely long life, even under severe conditions of use which might set up vibrations that would render the expensive exciting lamps which are essential to the operation of present. types of sound-reproducing apparatus unfit for service.

It is believed that the operation of my invention will be clearly understood from the preceding detailed description, it being evident that the film is threaded through the gate 10 of the projector 7 and around the sound sprocket 30 for connection to the receiving reel 9, the picture being focused for sharpness of definition and framed upon the screen by the usual adjustment of the head 11* of the lens barrel 11 and the ad,- justment of the right-angle support 21. Any necessary adjustment of the exciting lamp relative to the optical system and the focusing of the light beam projected from the latter may be readily and expeditiously efiected, it being understood that the alinement of the longitudinal axis of the beam with the median line of the film sound track is taken care of in the initial installation or attachment of the sound-head upon the projector through the medium of the elongated openings 13 and 14 in the frame 15 which permit of anynecessary lateral adjustment of the frame for this purpose. As the film traverses the sound sprocket 30, the light rays impingingthereupon will pass through the images of the sound vibrations in varying intensities for registration upon the oscillation-producing photo-electric cell, as previously described.

While the present disclosure'is directed to a preferred embodiment of my invention and certain described modifications thereof, various changes may be made in the details of structure and in the arrangement or association of the cooperating elements, without departing from the spirit and scope thereof. For example, the light-admitting valve or slit 36 may be relatively wider, as a slot, the thin line of light that should be admitted to the cell 35 to attain the desired degree of selectivity and the advantages which fiow therefrom, as hereinbefore set forth, being obtained by reducing the size of the reflecting medium as the mirror 34, to the requisite proportions; also the optical'system housing together with the light source housing may be rotatable upon their common longitudinal axis as a unit or independently to align the-axis of the light beam with that of the image of the vibration upon the film, as where the photograph may be disposed obliquely of the sound track, while the photo-electric cell housing may be rotated on a longitudinal axis or one between the horizontal and vertical to afford ready access to the sound.

to be projected through said system to excite said cell, a support common to all said soundhead elements, means for detachably and adjustably connecting a support to said motion picture projector, means mounted on said projector for passing film through the path of the light beam projected from said optical system, means supported in angularly-spaced relation to such film to receive light rays passing therethrough and transmit them at their full reception value to said photo-electric cell and rotatable means associated with said cell for variably controlling the amount of light admitted thereto.

2. The combination with a motion picture projection apparatus and a sound-head detachably connected thereto, said sound-head including an optical system, a photo-electric cell and a source of light associated with said optical system, of means for feeding film having a sound track disposed adjacent one edge thereof through the effective area of the light projected from said optical system, said means including a sprocket embodying a hub and a single row of radially-projecting teeth adapted to engage with the sprocket holes along one side of the film as it registers with said sprocket, the width of said hub portion being less than the width of the film, whereby the sound track area of the film will extend therebeyond and into the path of the light rays projected from said optical system, and means hehind said film for collecting the light rays passing through the extending sound track area thereof and transmitting them to said photoelectric cell.

3. The combination with a motion picture projection apparatus and a sound-head detachably connected thereto, said sound-head including an optical system, a photo-electric cell and a source of light associated with said optical system, of means for feeding film having a sound track disposed adjacent one edge thereof through the effective area of the light projected from said optical system, said means including a sprocket embodying a hub and a single row of radially-projecting teeth adapted to engage with the sprocket holes along one side of the film as it registers with said sprocket, the width of said hub portion being less than the width of the film, whereby the sound track area of the film will extend thereheyond and into the path of the light rays projected from said optical system, a light valve including an elongated opening and a rotatable shutter cooperating therewith for controlling the admission of light to said photo-electric cell and light-reflecting means associated with said sprocket for transmitting light rays passing through the extending sound track area of the film traversing said sprocket for registration with said lightadmitting valve.

4. The combination with a motion picture projection apparatus of a sound-head detachably connected thereto, said sound-head including an optical system, a photo-electric cell, a housing therefor, a source of light associated with said optical system, means for feeding film having a sound track disposed adjacent one edge thereof through the effective area of the light projected from said optical system, said means including a sprocket adapted to engage only with the film sprocket holes of the film along the edge thereof opposite to that with which the sound track is associated, the sound track area of said film extending beyond the film-supporting surface of said sprocket and into the path of light projected from said optical system, means for admitting oscillation-producing light waves to said photo-electric cell, said latter means including an elongated slit disposed longitudinally of said housing and a shutter cooperating therewith to vary the light-receiving area thereof, a reflecting surface angularly disposed behind the afore said extending sound track area of said film in alinement with said light wave-admitting means and a device for controlling the functioning of said light admitt ng means.

5. A sound-head assembly for use in apparatus for reproducing sound photographed on film, comprising an optical system having a housing, an exciting lamp, a housing therefor, said exciting lamp being adjustable within said housing means for supporting said optical system and said exciting lamp housings in co-axial alinement, a housing adapted to receive a photo-electric cell hinged to said supporting means in the horizontal plane of said optical system and exciting lamp housings, a light-admitting valve comprising an elongated slit formed in said photo-electric cell housing and shutter mechanism associated with said latter housing, for opening and closing said light-admitting means at will.

6. A photo-electric cell housing adapted to be associated with the elements of a sound-head for functioning in the reproduction. of sound vibrations photographed on film of a cylindrical configuration, the wall thereof being provided with an elongated narrow opening for admitting into the interior f said housing and a shutter embracing said housing formed with an opening adapted to register with the opening in housing, said shutter being rotatable upon said housing, at will, to open or close the light-admitting opening of the latter.

LOUIS J. SIMONS. 

